Guy problems........

Argh! Tis a very complex situation. Basically, since starting uni, I met this guy n we've got to know each other (as we live in the same areaish). It started with just random chatting on msn, but despite that he didn't really speak to me when we were at uni (taking same course, but he's the year above me). Which I thought was wierd, but was just friendly n everything, as he had a girlfriend.
Anyway, so after xmas, we started talkin quite a bit more often on msn, then eventually he told me he was having probs with his girlfriend and told me pretty much everything about her this one evening and so talked him through it n then after he was like 'it was nice being able to talk to someone impartial' so was like k. We talked a bit more, n he told me when he broke up with her n i thought this was a tad bit wierd, as didnt really know him, but anyway.
Then over the last couple of weeks have kinda realised I really liked him, and all of a sudden he starts talking to me in the corridor n things, n was like ok, but yay! Then there was a ball this saturday n despite all his friends getting on this one bus, he waited with me n my friends and got on this other one, then saw him generally through the night, then got with him at the end of the night. Then he came back to mine, we slept together and he didn't leave till 7pm last night (so that was.....15 hours we were together). Which, when I thought about it yesterday, was like yay! that seems good, from analysing things, n when i saw him today, he was really sweet and nice. However on saturday night, he was bothered about going anywhere near his ex when he was dancing with me, n i was like uh-oh- slight bit wierd. Then tonight (as been out on pub crawl), sent him a text midway through the night, just for the banter, as he hadn't turned up, n got one back saying 'sorry, have had a load of **** tonite to deal with, where are you upto?' N first thing i thought was uh-oh its his ex again, and sure enough, he comes in, is like 'hi, how are you? Can i speak to you?' n before he even had chance to say nethin, i was like 'its your ex isnt it' n he was like 'yeah', n i thought sh**! So he was like, i've just got a lot of sh** on my plate at the mo to sort out, n your a lovely girl (oh feff off!), but i just need to sort this stuff out. He was like we mite have another go at it sometime- he worded it differently than this,- a way in which made me think he could be talking about his ex (n him getting bk together). But basically, it COMPLETELY ruined the rest of my night, as was sooooo happy yesterday, dammit! Oh yeah, n his ex was the year above him, they were together for 4months n broke up a month ago. According to him she's really unconfident n has very little self esteem, but she's really pretty, intelligent n has everything going for her, n now i feel really guilty n sorry to her, for my behaviour, althought they werent together when things happened with me and him, but still feel awful. God, even as im writing this, i know what the replies are going to be, but just in case im wrong-
What is the general consensus?- was i a delayed rebound or does he actually like me, but feels he has to sort out stuff with his ex first? Oh lord, i HATE it when this happens in life! But alas, it wouldn't be as fun without it would it- haha! Replies would be greatly appreciated! Thanksx